Two studies of neurologic sequellae of perinatal complications are proposed. Using data from Danish population registers, the first study examines the association between post-term (>42 weeks) delivery and risk of epilepsy in childhood. Birth data on over 300,000 singletons born in Denmark in 1980-2001 are available. Risks epilepsy in the first 12 years of life are estimated for the entire post-term delivery group, and for each week of prolonged gestation. These are then compared with the epilepsy risk among term babies (38-42 weeks). Risk ratios are examined in the groups according to birth weight, mode of delivery, birth presentation, maternal age at delivery, and smoking. Cox's regression will be used to obtain adjusted risk ratio estimates while accounting for differential follow-up. The second study focuses on suboptimal (<7) 5- minute Apgar score as a clinical predictor of lowered cognitive function and sensory acuity. Birth registry data from Danish draftees born in 1978-1983 are linked to the results of standardized intelligence, hearing, and vision tests from the Draft board. Tests' results are compared for those with suboptimal vs. normal Apgar score. The association is further examined according to other perinatal variables as in the first study.